Evaluation of analysis methods of the semi-circular bend (SCB) test results for measuring cracking resistance of asphalt mixtures

This paper includes a large study to investigate the effect of different mixture design parameters (percent binder replacement, binder modification, low-temperature binder grade, aging, and mix design traffic level) on resistance to fracture using the Semi-Circular Bending (SCB) test at Intermediate Temperatures. The results show that the Jc parameter estimated from the SCB test cannot be directly related to the controlled parameters investigated in the study. Therefore, post-peak data analysis using the concept of Flexibility Index (FI) parameter from the Illinois Flexibility Index Test (I-FIT) is used in this study to analyze the data obtained from the SCB test. Statistical analysis (ANOVA and multi-linear regression analyses) are used to show which of the response parameters are statistically affected by mixture design factors. The study shows that although the SCB tests provide results that allow determination of various parameters such as Jc, peak load, FI parameter, and post-peak-slope, only the FI parameter can detect the effect of aging and show clear sensitivity to specific mixture design factors.